Uniform pressure responses for nanomaterials-based biological on-skin flexible pressure sensor array

Abstract

Nanomaterials-based flexible sensor array has been receiving tremendous interest for uses in the fields of wearable devices, healthcare monitoring, and biomedical application. However, flexible sensor technology, whose active sensing element is introduced by nanomaterials, presents common practical problems such as mismatch and deviation in integration for sensor array architecture. In particular, sensor elements in array that are attached to the skin and then experience different bending strains suffer from non-uniform pressure responses, thus being a significant obstacle to commercialization. To provide a solution to these problems, we here propose an electrical circuit method for obtaining uniform pressure responses in nanomaterials-based on-skin flexible pressure sensor array. The proposed method employed by cubic spline interpolation achieve a wide range of calibration for operation in sensor array. The uniform responses were confirmed in a 4 × 4 pressure sensor array with the piezo-resistive characteristics due to graphene nanoplatelet (GNP) used as active material. The calibrated responses are demonstrated on the flexible sensor array attached to a human arm having uneven surface curvatures on which each sensor in the array may experience different bending strain. This work has opened the way to give reliable responses in resistance for wearable electronic sensor array attached to the body despite different external stress, and is an approach that can be extended to various sensor technologies.